Realised gains/losses are profits or losses from actual sales of assets. Unrealised gains/losses are paper profits/losses on assets you still own. Understanding the difference is crucial for tax planning and portfolio assessment.
Many investors confuse their portfolio's current value (unrealised) with actual taxable income (realised). This can lead to poor tax planning and unrealistic expectations about available cash.
You bought 100 shares of NVDA at $100/share ($10,000 total):
You can't spend unrealised gains. They're locked in the asset until you sell.
Understanding realised vs unrealised helps you: